Weller WD1 Display Broken

[khales6]

Hi all,

I have owned this WD1 for several years, but I must admit I have not really used it all that much. I got it out to use the other day and the LCD display seems to be missing about half its segments. Upon power up, the display does not "light" the large temperature digits except the left most of the three, which only show as an E. The iron does heat up and it seems that the readout is trying to display the temperature, The aforementioned left digit seems to increase if you interpolate the missing two segments of the E. The preset buttons seem to change the temperature. I have opened up the case, and looked around. I don't see any obvious problems, but I really don't know what to look at. I do see one solder joint on the LCD that doesn't look proper but likely is okay. Unless this is a problem someone else has experienced, I don't know if I have the skills to dig too deep into testing. Anyone have any experience with this one, or can suggest where/who might be able to repair it? It's still open, so I could shoot some pictures if that is helpful.

Thanks,

Kelly

[Zucca]

I am not an expert, can you post some pictures?
Thanks!

[snellface]

I am more or less the exact same issue, except that the first time it was only the top of the right most digit that went missing and now the top of all the digits are missing. However i think i have the WD1M model.

Did you have any success repairing your unit? I'm currently probing around, but i don't know which LCD pins relate to which segment yet.

[t1d]

A common problem with displays that are only showing part of their digits is simple contact issues. For any wire leads going to them, note their orientation, remove them, clean all contact points and re-seat them.

Some displays use a contact bar, instead of individual contact points. Those can need cleaning, also. But, sometimes, they just lose physical contact. Try gently pressing on the display and see if anything changes.

Try these things and let us know your results. Please post pictures. We are working in the blind.

[wraper]

If the LCD is a type with terminals which are soldered, most likely it's an issue with IC which drives LCD.

[lapi]

The missing segments in the WD1 LCD display appear to be caused by the degradation exposed ITO traces connecting the pins to the traces inside the LCD cell. That commonly happens over time, faster in humid environment. One may be able to repair the connections with silver paint over the traces but that may not always work and requires quite some care not to make shorts between the trades to different pins. I was able to repair the traces temporarily with graphite paste while reverse-engineering the segment/back-plane mappings to pins.

For a reliable fix I used the information so acquired and the datasheet of the display controller chip to implement an I2C to 16x2 character LCD bridge with a PIC microcontroller, thereby providing the functionality as in the original display with the standard character module. Description of the solution along with the microcontroller firmware (hoth source and HEX) are available in https://hackaday.io/project/188741-replacing-broken-lcd-of-weller-wd1